Photographs of Gentoo Penguins nesting with their chicks at Edinburgh Zoo May, 2015.
This is by far in my opinion the best penguin enclosure I have seen and I have read that it in fact the largest outdoor pool in Europe. Prior to this in March the zoo provides the nesting platforms (sheltered to keep chicks out of direct sunlight) and put an array of pebbles within the enclosure. The males of the breeding females select the best pebbles and present them to the females and then a pebbled nest is built on the provided platforms the female to lay her eggs on and then nurse her chicks.
I cannot remember how many chicks there was at the time but there were several nesting females and I read an article from 2016 saying that they had 22 chicks which is amazing (http://www.edinburghnews.scotsman.com/our-region/edinburgh/corstorphine/gentoo-penguin-chicks-weighed-at-edinburgh-zoo-1-4159223).